Steam trap



June 2, W K. SIMPSON STEAM TRAP Filed July 28, 1932 2 Sheets-Sheet 1 f fif i|| V y /7 l ,l m" 23 June 2, 1936 l Filed July 28, 1932 w. K.SIMPSON' STEAM TRAP 2 Sheets-Sheet 2 Iii/22257 Wfmwff Patented June 2,1936 UNITED STATES .PATENT OFFICE STEAM TRAP Application July 28, 1932,Serial No. 625,451

4 Claims.

This invention relates to traps for the separation of the air and waterof condensation from steam, in steam heating Systems and othersituations where such a separation is called for. The main object of theinvention is to produce an improved trap of this character which issimpler, and may be made more compact, than traps of the same classheretofore known, and of which the water discharge valve is operablewith a minimum application of force. A corollary object is to furnish insuch a trap a balanced discharge valve with means for adjustment wherebyboth elements of the balanced valve structure may be caused to closeequally tightly. Another object is to combine the foregoingcharacteristics with thermostatic means for controlling the discharge ofair from the trap. The invention consists in the nov-e1 and improvedfeatures hereinafter described and all equivalents thereof within thescope of the appended claims.

Two embodiments of the invention are here shown and described. One ofthem is designed more particularly for use with steam heating systemswhich operate at low pressures and is known commercially as a drip trap.The other is designed for heavier duty, to be used in situations wheremuch higher steam pressures are employed, for instance pressures up tothirty pounds or more per square inch, and is called commercially ablast trap or heavy duty trap.

In the drawings,-

Fig. l is a plan View of the drip trap above referred to;

Fig. 2 is a vertical section of this trap taken on line 2 2 of Fig. 1;

Fig. 3 is a fragmentary vertical section taken on line 3 3 of Fig. 1;

Fig. 3a. is a perspective view of the valve seat fitting;

Fig. 4 is a front elevation of the heavy duty or blast trap abovereferred to;

Fig. 5 is a vertical section of the latter trap taken on line 5-5 ofFig. 4;

Fig. 6 is a fragmentary sectional view of the thermostatic air ventvalve and its mounting;

Fig. 7 is a fragmentary plan View in horizontal section taken on line'I-l of Fig. 5;

Fig. 8 is a fragmentary sectional View of the water discharge valve andassociated parts.

In the foregoing drawings the blast trap is shown in Figs. 4 and 5 on arelatively smaller scale than the representation of the drip trap inFigs. 1 and 2. As manufactured the blast trap its substantially largerand stronger than the drip rap.

The form of trap shown in Fig. 1 has a shell or casing II ofsubstantially cylindrical form, adapted to be used with its axisupright. It is open at the upper end over which is placed and secured acover I2. In one side near the top of the trap casing is a threadedopening I3 into which is screwed a part of the return line pipingthrough which air, water of condensation, and 10 exhaust steam flow fromthe radiators or pipe lines. In yanother part of the casing wall is acored passage I4 having a branch I5 which extends partially into thebottom of the trap casing, and on the outside a tapped opening I6 intowhich the outlet pipe from the trap is screwed. The upper part ofpassage I4 is made wide enough to contain a thermostat I1; and throughthe inner wall of this passage there is a threaded opening in which isscrewed a Valve seat fitting I8. The wall which bounds the outer side ofthe passage is here made with a large enough opening to admit thethermostat, which opening is closed by a removable cap I9 screwed intoit.

The thermostat is a drum having distensible V.end walls, to one of whichthe valve member 20 is secured, and the other one of which carries astem 2| passing through and made fast to the end wall of a cage 22. Thiscage surrounds the thermostat and its rim is seated in a recess 23formed in the partition wall between the passage I4 and the main chamberof the trap; while the outer end of the cage carries a spring 24reacting against the cover I9, and holding the thermo- 35 stat and cageassemblage in place. A vent port 25 is formed in the valve seat fittingI8 in line with valve 2|! so as to be closed and opened by said valve asthe thermostat expands and contracts. f 40 The overlying wall 26 of thebranch passage I5 is finished smooth on its top side, through which a,port 21 opens, and supports a discharge valve fitting 2B, in leakagetight Contact with the linished under surface of the latter. 'Ihe valveiit- 45 ting 28 has lugs 29 at opposite sides through which bolts 3i)pass. Said bolts also pass through the wall 26 and the bottom of thetrap, and receive cap nuts 3| on their outer ends. The cap nuts havebeveled faces which .fit into tapered 50 recessesin the bottom of thetrap body and prevent leakage.

The valve seat fitting 28 has a port 32 in alinement with the port 2l.It projects thence across the axis of the trap body where it overhangsthe bottom of the trap. It has a tapped hole 33 in its top side whichreceives an adjustable screw threaded valve seat bushing 34, and a port35 in its bottom wall alined with a port 36 in such bushing. Except forthe ports 32 and 35, and the hole 33, the tting 28 is an entirelyenclosed hollow body.

A balanced discharge valve cooperates with the ports 35 and 36, having adisk or valve element 3I adapted to seat on the upper rim of the port35, and a second valve disk or element 38 adapted to seat on the upperrim of port 36. disks are each made, with associated stem extensions, asa separate piece from the other, and are screwed together, by a threadedextension 39 on one stem entering a socket in the other, to permit theirassemblage with the bushing 34. The connected valve disks are secured toa float 40 by a threaded stem 4| projecting from the disk 38 and screwedinto a nipple 42 which passes through the bottom of the oat and receivesa cap nut 43 on its external thread.

Y The float, valve units, and valve seat fitting are assembled togetheroutside of the trap body or casing, with the bolts 35 driven tightlyinto the lugs 29 of the fitting and prevented by iiutes in their sidesfrom turning, and are inserted as a unit in the casing, the cover I2being removed. In order to enable the bolts to be easily registered withthe holes in the trap body at this time, I preferably employ means forpreventing rotation of the valve fitting relatively to the float. Suchmeans in the present illustration consists of a yoke 43a, through themiddle of which the threaded stem 4I passes, and the extremities ofwhich are turned down so as to embrace loosely the sides of the Valvetting. This yoke may be gripped between the valve disk 38 and theadjacent end of nipple 42. However, other means of attachment within theskill of the mechanic may be used for the same purpose.

When the trap is cold and empty of water, its parts take the positionshown in Fig. 2, the balanced exhaust Valve being closed and thethermostatic vent valve being open. When steam is These valve turnedinto the system, air and water of condensation flow into the trapthrough the inlet I3 and air escapes through the vent 25, passage I4,and outlet I6. When enough water has accumulated to raise the float,discharge of water occurs through the ports 35, 36 and connectingpassages and ports, to the outlet I6. When steam reaches the trap, orapproaches so near it that its heat expands thermostat I1, the ventvalve closes.

By virtue of the balanced construction of the discharge valve, the forceneeded to open it is a minimum. Thus it may be opened and closed by aoat of small volume directly coupled with it; while the ports may be ofany desired diameter without effect on the ability of the float to openthe valve. The float indeed need have only enough buoyancy to supportthe weight of the valve and yoke, and lift them, besides overcoming whatfrictional resistance there may be to their rise. The permissible smallsize of the oat and elimination of leverage for multiplying its forceapplication on the valve, and the large possible size of the dischargeports, permit the trap to be made small and compact, while able todischarge a large volume of water. It combines maximum dischargecapacity with minimum bulk, weight and cost.

The depression 44 in the bottom of the trap permits collection of scaleand sediment which otherwise might interfere with the tight closing andproper operation of the valve. A cleanout hole in the bottom wall,closed by a removable plug 44a, enables such matter to be removed.

An important factor conducing to the results above explained is theadjustable valve seat bushing 34, the adjustment of which enables bothValve disks to be seated simultaneously and with equal tightness,without diflicult and extensive procedures of machining within minutelimits of error, or tedious grinding of the valves on their seats.

The trap shown in Figs. 4-8 is essentially the same in principle as thatjust described and differs only in features of. design and details ofmanufacture. Its body or shell |8a is open at one side and receives acover 45 across the open side. In the upper part of the cover is aninlet opening |311, and in its lower part an outlet opening Ga fromwhich a hollow extension 28a, closed at'the sides and inner end, runswell into the interior of the shell. This extension has alined holes 46and 41, one of which is threaded, in its top and bottom sides, in whichis placed a valve casing 48 which has a flange 49 to overlie the rim ofhole 46. Ports in the sides of this casing open to the interior space ofthe extension 28a. In the lower part of the casing is a flange 56surrounding a port 5| and containing a seat for a valve disk or element52. Its lower extremity is made as a yoke 53, having a central hole forguiding the tail stem 54 of this valve unit, and being open at oppositesides for free iiow of water. The upper end of the casing is open andreceives in threaded connection with it a yoke 55 which guides stem 56,and is open at opposite sides. In the interior of. the yoke 55 isadjustably screwed a Valve seat ring or bushing 5l having a central portand a seat which cooperates with valve disk or element 58. The two valveelements are constructed separately and are detachably screwed togetherat 59 for assemblage. Stem 56 is screwed into a tapped hole in thebottom of a float 60.

This construction provides a balanced valve, of which both ports may beof the same area, or the lower port may be somewhat larger than theupper in order to assist the opening movement when the iioat rises, butnot enough larger to open the valve when the full weight of the floatrests on it, even when aiected by the heaviest steam pressures underwhich the trap is used. Or, conversely, the upper port may be the largerif a stronger closing effect under pressure is desired. In principle,and to a considerable extent in detail also, it is identical with thebalanced valve previously described; of which, also, the ports may beequal or unequal in area, as and for the purposes just explained. Theterm balanced as used to denne the valves herein described is to beunderstood as including structures wherein the pressure acting on onevalve element partially balances that acting on the other, as well asarrangements where the balance is exactly equal.

A thermostatic vent is provided for this trap also. It comprises a tube6I threaded into a tapped hole in the top side of extension 28a andrising into the upper part of the trap above the highest water level ofnormal operating conditions. Such tube contains a valve seat bushing 62in its upper end on which is mounted a cage 63 supporting a thermostat64 and having openings 65 for flow of air. The thermostat in this casealso is an expansible drum containing a volatile fluid, to one wall ofwhich is secured a valve 66 for opening and closing the passagewaythrough the bushing 62; and from the oppo- 75 site wall projects athreaded stem which passes through the detachable cover of the cage andreceives a clamp nut (Fig. 6).

The mode of operation and advantages of this trap are substantially thesame as described in connection with the drip trap. It is provided witha spherical float instead of a cylindrical one to combine minimum weightwith maximum strength to resist collapse under heavy uid pressures.

A strap or bracket 6l is secured to the upper part of the trap by one ofthe bolts which holds the cover, and serves for the attachment of achain, rod, etc. for supporting the Weight of the trap when it isconnected in a suspended pipe line.

The valve units and float (being the movable parts) of this trap arewithheld from movement while the trap is being moved about in shipment,by a rod 68 screwed into a tapped hole in the end of valve stem 54 andpassing thence through a hole in a plug cover 69 which is set into atapped hole l0 in the trap bottom. The outer part of this rod is bentover against the outer side of the plug at H. This prevents injury tothe valve units and seats by vibration and careless handling in transit.When the trap is set up for use, the rod 68 and plug cover 69 are takenout and discarded. Hole lil is then closed by a threaded plug l2, whichmay be removed when necessary to drain the trap and clean out sediment.In

like manner the valve units of the trap shown in Fig. 2 may be heldagainst their seats, for shipment, by substantially identical means;since the hole in the bottom of the trap (occupied by the removable plug44a) is approximately in line with the lower valve stem extension. Thusa tension member equivalent to the rod 68 may be connected with saidextension `and interlocked with a temporary cover or the like, set in orover the clean out hole in substitution for the plug 44a.

What I claim and desire to secure by Letters Patent is:

inlet and outlet openings, a valve tting, a balanced valve cooperatingwith said fitting, and a float connected to said balanced valve, allconstituting a unit assemblage insertable as such into the casing andthe fitting having a port to register with the outlet opening of thetrap casing, means for securing said valve iitting in the casing,including parts in the tting and casing which must rst be brought intoregister, and means for preventing rotation of the fitting relatively tothe Valve in the course of entrance into and assemblage with the trapcasing.

2. A steam trap as set forth in claim l, inl

which the rotation preventing` means comprises a yoke having anon-rotative engagement with the float, and members loosely embracingopposite sides of the fitting in a manner to prevent rotation whilepermitting free endwise movement of the float and valve relatively tothe fitting.

3. A steam trap comprising a casing having an outlet in its lower partand a smooth finished surface surrounding said outlet, a fitting havinga finished surface complemental to the rst named nished surface andadapted to make fluid-tight contact therewith, said fitting having ahole to register with said outlet and being otherwise of closed hollowformation with alinecl ports in two walls which are opposite to oneanother; the casing and fitting having complemental fastening means forsecuring the fitting in place, a balanced valve cooperating with saidport, and a oat secured to said balanced valve; the float, valve, andfitting being a unit assemblage separate from the casing, adapted to beinserted in the casing as such.

4. A steam trap as set forth in claim 3 comprising further means forpreventing relative rotation between the tting on the one hand and thevalve and iioat on the other hand when such unit assemblage is placed inthe casing to be secured therein; such rotation-preventing meanspermitting opening and closing movements of the valve.

WILLIAM K. SIMPSON.

